JPH07286598A - Centrifugal fan provided with fluid deflector - Google Patents

Abstract

PURPOSE:To provide a centrifugal fan of high efficiency by reducing fluid pressure loss of a fluid deflector to prevent peeling of fluid, and improving flow. CONSTITUTION:A flow regulation plate 8 is provided on the inner side of a fluid deflector 6 of a plate thickness (t) formed in the form of a horn, a blade entrance width of an impeller is B, an axial distance between a side plate 4 and the flow regulation plate 8 is W, an inner diameter of the fluid deflector 6, a half peak angles of two conical surfaces of the flow regulation plate 8 are alpha beta (alpha+beta), an entrance inner diameter of the flow regulation plate 8 is D2, an inner diameter of a crossing circle of the two conical surfaces is D2, a depth inner diameter of the flow regulation plate 8 is D3, and a shaft diameter of a rotor l is d1, then 0.2B<=W<=0.3B, (0.5D1<2>+0.2d1<2>)<1/2=D2<= (0.7D1<2>+0.8d<1>2)<1/2>, (0.7D1<2>:0.3d1<2>)<1/2=D3<=(0.9D1-<2>+0.9D1<2>+0.1d1<2>)<1/2>, D4=D1+2t0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the performance of a centrifugal fan with a fluid deflector for bending and guiding ventilation.

[0002]

2. Description of the Related Art A conventional centrifugal fan with a fluid deflector will be described with reference to FIG. FIG. 3 is a schematic sectional view of the centrifugal fan with a fluid deflector. The centrifugal fan is provided with a rotor 1, an impeller including a main plate 2, side plates 4, blades 3 and a cap 5 attached to the rotor 1 and a suction port. And the fluid deflector 6 that is formed. The airflow 9 flowing into the centrifugal fan is bent in the radial direction by the fluid deflector 6 in the axial direction, and the axial flow is bent again in the radial direction to flow into the impeller. As described above, in a centrifugal fan with a fluid deflector having a function of bending a radial flow in an axial direction and then bending an axial flow in a radial direction, reduction of pressure loss and improvement of flow by optimizing a shape of a fluid deflector can be achieved. , Is an important factor for improving the performance of centrifugal fans.

Next, the operation of the conventional example will be described. In the centrifugal fan, the air flow 9 passes through the fluid deflector 6 from the base 5 of the rotating impeller in the axial direction, changes in the radial direction, and is discharged through the vanes 3.

[0004]

The fluid deflector is effective for improving the fan efficiency, but unless a proper fluid deflector is used, the pressure loss increases and the flow of the fluid is disturbed to lower the fan efficiency. The fan may stall due to flow separation. If a multi-arc structure is used to obtain an appropriate fluid deflector, it will be difficult to manufacture and the manufacturing cost will be high.

An object of the present invention is to provide a highly efficient centrifugal fan at low cost by reducing the fluid pressure loss of the fluid deflector, preventing fluid separation and improving the flow.

[0006]

A centrifugal fan with a fluid deflector according to the present invention is formed in a trumpet shape and causes a fluid flowing inward in the radial direction to flow in an axial direction and then radiates a fluid flowing in the axial direction. In a centrifugal fan in which an impeller, which is a rotating body, is disposed inside a fluid deflector having a function of bending in a direction, a flow straightening plate 8 formed of two conical surfaces is provided inside a fluid deflector 6 having a plate thickness t. Let B be the blade inlet width of the impeller, W be the dimension from the side plate 4 of the impeller to the rear end position of the flow straightening plate mounting, the inner diameter of the cylindrical portion of the fluid deflector is D ₁ , and the inner diameter of the flow straightening plate 8 on the inlet side is D. ₂ , the outlet inner diameter is D ₄ , the inner diameter of the intersecting circle of both conical surfaces forming the straightening plate 8 is D ₃ , the half apex angles of the front and rear conical surfaces are α and β (α <β), and the rotor 1 when the diameter of the shaft and d _1, 0.2B ≦ W ≦ ^{_{.3B, (0.5D 1 2 + 0.2d}} 1 2) 1/2 ≦ D 2 ≦ (0.7D 1 2
+ 0.8d ₁ ² ) ^1/2 , (0.7D ₁ ² + 0.3d ₁ ² ) ^1/2 ≤ D ₃ ≤ (0.9D ₁ ²
It is characterized in that + 0.1d ₁ ² ) ^1/2 and D ₄ = D ₁ + 2t.

[0007]

By practicing the invention, the fluid flows along the fluid deflector 6 and is then deflected from the axial direction to the radial direction. The current plate 8 is placed at a position where the direction of the fluid flow is changed.
Since the fluid flow is bent from the axial direction to the radial direction on the way, partial separation and vortex are prevented from occurring in the side plate side flow 10 near the base of the impeller, and the flow flowing into the blade inlet is Can be rectified to improve fan efficiency. As a result, the fan efficiency is increased by about 20% as compared with the conventional centrifugal fan with a fluid deflector. Further, there is an advantage that it can be manufactured at a lower cost than a fluid deflector composed of multiple arcs having the same efficiency.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic sectional view of a centrifugal fan with a fluid deflector according to a first embodiment of the present invention, and FIG. 2 is AA of FIG.
FIG. In the figure, a straightening vane 8 having two conical surfaces is joined to the inside of a fluid deflector 6 formed in a trumpet shape in the radial direction via a plurality of ribs 7. The rotor 1 and the impeller composed of the main plate 2, the blades 3, the side plates 4 and the cap 5 are inserted into the center of the fluid deflector 6 and the fluid deflector 6 is inserted.
It is rotatably installed around the center of. Let B be the inlet width of the blades 2 and W be the axial dimension up to the inner end faces of the side plate 4 and the straightening plate 6.

The inner diameter of the fluid deflector 6 having the plate thickness t is D ₁ , the inner diameter of the rectifying plate 8 on the inlet side is D ₂ , and the inner diameter of the rectifying plate 8 is D ₄ on the intersection circle of the front and rear conical surfaces forming the rectifying plate 8. When the half-vertical angles of the inner diameter D ₃ are α and β (α <β) and the shaft diameter of the rotor 1 is d ₁ , 0.2B ≦ W ≦ 0.3B, (0.5D ₁ ² + 0.2d ₁ ² ) ^1/2 ≤ D ₂ ≤ (0.7D ₁ ²
+ 0.8d ₁ ² ) ^1/2 , (0.7D ₁ ² + 0.3d ₁ ² ) ^1/2 ≤ D ₃ ≤ (0.9D ₁ ²
+ 0.1d ₁ ² ) ^1/2 and D ₄ = D ₁ + 2t.

The operation of the first embodiment will be described. Airflow 9
Changes its direction from the axial flow to the radial direction at the position of the flow straightening plate 8 along the fluid deflector 6, so that partial separation and vortex of the flow generated in the side plate side flow 10 near the base 5 of the impeller are generated. Prevent and improve the flow rectifying the flow entering the blade inlet. Due to the above action, the fan efficiency is increased by about 20% as compared with the conventional centrifugal fan with a fluid deflector. Further, it can be manufactured at a lower cost than a fluid deflector composed of multiple arcs having the same efficiency.

[0011]

According to the present invention, a fluid flow can be made smooth, fluid pressure loss can be reduced, centrifugal fan efficiency can be improved, and a highly efficient centrifugal fan can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a schematic drawing of a centrifugal fan with a fluid deflector according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic sectional view of a conventional centrifugal fan with a fluid deflector.

[Explanation of symbols]

1 ... Rotor, 2 ... Main plate, 3 ... Blade, 4 ... Side plate, 5 ... Base, 6 ... Fluid deflector, 7 ... Rib, 8 ... Rectifier plate, 9
... air flow, 10 ... side plate side flow.

Claims (1)

[Claims] 1. A rotating body is provided inside a fluid deflector which is formed in a trumpet shape and has a function of causing a fluid flowing inward in a radial direction to flow in an axial direction and then bending the fluid flowing in the axial direction in a radial direction. In a centrifugal fan having a certain impeller, a flow straightening plate (8) formed of two conical surfaces is provided inside a fluid deflector (6) having a plate thickness t, and the impeller blade inlet width is set to B. , W is the dimension from the side plate (4) of the impeller to the rear end position of the straightening vane, the inner diameter of the cylindrical portion of the fluid deflector is D ₁ , the inner diameter of the straightening vane of the straightening plate (8) is D ₂ , and the inner diameter of the outlet is D ₄ , the inner diameter of the intersection circle of both conical surfaces forming the straightening vane (8) is D ₃ , the half apex angles of the front and rear conical surfaces are α, β (α <β), and the rotor (1) axis is when the diameter as _{d 1, 0.2B ≦ W ≦ 0.3B} , (0.5D 1 2 +0.2 ^{_{1 2) 1/2 ≦ D 2 ≦}} (0.7D 1 2
+ 0.8d ₁ ² ) ^1/2 , (0.7D ₁ ² + 0.3d ₁ ² ) ^1/2 ≤ D ₃ ≤ (0.9D ₁ ²
A centrifugal fan with a fluid deflector, characterized in that + 0.1d ₁ ² ) ^1/2 and D ₄ = D ₁ + 2t.